Treacherous Mansion Gems

There are 13 Diamonds to be found in the Treacherous Mansion, and certain gems can only be obtained in certain missions, though most gems that appear in a certain mission can also be obtained in later missions(Gems found in E-1 cannot be found in later missions). The gems listed are in the order they can be obtained, and in the order they appear in the gem collection screen.

diamond 1 - Undergound Lab (Available in E-1)

After clearing the Underground Lab, using the electricity wheel will zap the Suit of armor, causing the helmet to fall off. You can then use it to smash the jars, one of which contains a gem.

Diamond 2 - Haunted Catacombs (Available in E-1)

Before following the Polterpups tracks in the second half of the Haunted Catacombs (after going through the Underground Lab), inspect the suit of armor with the sword. The suit will 'point' with the sword to the next corridor. Follow the trail via the suits of armor and the area they point to with their swords. The last area has no suit of armor, so head north to reveal one with the darklight, then follow his direction right to a portrait of a ball of web and a fire. Bring the flaming ball back to where a wall of webs were to light it up, revealing a gem.

Diamond 3 - Haunted Catacombs > Cliffside (Available in E-1)

In the Haunted Catacombs, follow the pointing suits of armor until you arrive at the corridor with the web wall holding Diamond 2, then move south twice to find a door to the opposite side of the Cliffside, where a gem will be waiting on a vine.

Diamond 4 - Front Entrance (Available in E-2)

Cast the Darklight on the gargoyle the right side of the stairs to reveal a chain. Pull the chain to reveal a hidden safe under the stairs. It is guarded by an Empowered Slammer, so take him out to claim the gem.

Diamond 5 - Restrooms (Available in E-2)

In Grand East there is a door leading to the Restrooms, but another side of the Restroom can be seen. Shine the Darklight to reveal a door leading to the other side of the Restrooms, and yank the chain on the toilet to have a gem pop out.

Diamond 6 - Ice Age Exhibit > Gargoyle Roof (Available in E-2)

In the Ice Age Exhibit, yank on the Mammoth's trunk to be yanked up and through the roof to the Gargoyle Roof. An incomplete constellation of stars could use some help. There is a star floating through the sky, one on the ground near Luigi, and one in the mouth of a Gargoyle. Grab them and punt them out with the Poltergust to form a complete star made of stars, and a gem will be yours.

Diamond 7 - Ancient Exhibit (Available in E-2)

Using the bucket from the Dark Age Exhibit, and filling it with the water from the Jungle Exhibit, take the filled bucket to the Ancient Exhibit and climb the long path back up to the main level to find a seedling near a tree. Water it and receive a gem in return.

Diamond 8 - Aviation Exhibit (Available in E-3)

Head into the Aviation Exhibit, and pull one of the sandbags from the hot air balloon. An Empowered Hider and two Greenies will spring forth. Capture them, and then pull the other sandbag to reveal a gem.

Diamond 9 - Nautical Exhibit (Availabie in E-3)

After taking control of the Nautical Exhibit, activate the portal, and grab a log from the Jungle Exhibit. Take the log and dump it on the platform on the right side to lower other other steering wheel blocking the door. Head out the door to find a chest with a gem.

Before entering the Train Exhibit, there are several things to do that you may not have time for in later missions. To start, grab one of the bubble plants from the Study, and enter the portal to return to the Front Entrance. Float upwards and to the right and find a small landing with a gargoyle with a book in his mouth. Make him drop it and bring the book back to the Dark Age Exhibit to find a gem.

Diamond 11 - Study > Jungle Exhibit (available in E-3)

Take a bubble plant from the Study and go to the Jungle Exhibit through the portals. Float up to the upper level, and look for a gold bubble plant. Grab it to start a coin minigame. The trick is to fly against the moving coins to grab them that much faster. Collect them all and be rewarded with a gem.

Diamond 12 - Study > Ice Age Exhibit (Available in E-3)

Grab a bubble plant from the Study and head to the Ice Age Exhibit through the portals. Float up to the upper level and look for a gold bubble plant. By grabbing it, a coin minigame starts. Follow the paths of coins going out the air conditioners to get all of the coins before time runs out. The prize is a chest with a gem inside.

Diamond 13 - Train Exhibit (available in E-3)

Use the darklight on the floor to reveal a missing set of tracks, which brings a large train into the room. Step on for the ride of your life, and get a gem for your troubles.